Smoke-preventer.



B. F. B. FAIRBROTHER.

SMOKE PREVENTER.

APPLICATION FILED FEB.15,1912.

Patented Feb. 24, 1914,

wflmessesz maI LJ-UUA f UNITED STATES; PATENT oFiuoE.

BENJAMIN F. B. remnzeo'rnnn, or xnmm, NEW HAMPSHIRE, ASSIGNOR 'ro CHARLES 1 K. DARLING, or CONCORD, MASSACHUSETTS.

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T0 all whom it may concern:

Be it known that I, BENJAMIN F. B. FAIR nnornnu, a citizen of the United- States, and resident of'Keene, in the county of Cheshire and State of New Hampshire, have invented certain new and useful Improvements in Smoke-Preventers, of which the following is a specification.

The object of the present invention is to provide means for mixing fresh air with the fuel gases in a fire-box and for holding such air and gases in the fire-box longenough to completejthe combustion of the gases before they'pass out of thefi-re-box. v

Of the accompanying drawings which illustrate the invention as applied to a 1000; motive boiler: Figure 1 represents. a longitudinal vertical section of a locomotive,

more or less conventionally shown. Fig. 2 represents on. a larger scale a section through the door through which fuel is passed into,

the fire-box, which door is a support for a fan and motor by which the'desired currents are set up inthe fire-box. Fig. 3 represents an elevation of the fan in the fuel opening. Fig. f is an elevation of the lower ,part of the water-jacket .in front of 'the' fire-box.

Fig. 5 is a vertical section of a fan casing prov1ded with screens. Fig. 6 1s a vertical.

section of an air tube provided with screens. The same reference characters indicate the same parts wherever they occur. f

The fire-box or fuel chamber of the boiler is indicated at A, and'the grate therefor is indicated at B. The main water space of the boiler is indicated at C, and the fire-tubes which extend therethrough are indicated at D. The smoke-box at theforward end of the boiler is-indicated at 'E, and the smoke stack at F. The'usual arch in the fire-box is indicated at G, and the door through which the fuel is supplied is indicated at H.

The elements thus far enumerated may be of any well known or desired construction and arrangement.

The chief cause of smoke is lack of oxygen. Without the necessary supply of oxygen the combustible gases will not be completely consumed but will passthrough the fire-tubes and smoke-stack in the form of smoke and will cause a deposit of soot in the fire-tubes which greatly impairs the efl'iciency of the boiler and which requires frequent cleaning of the tubes in order to keep them sufiiciently clear for the passage of the Specification of Letters Patent.

' of the locomotive.

Patented Feb. 24,1914.

Application filed February 15, 1912. Serial No. 677,758.

gases. In the majority of boilers no prov sion is made for supplying fresh air to the fire-box except that which may enter through the grate and fuel. During most of the time when a boiler is in operation, the grate is so clogged with ashes and clinkers and by the fuel that the desired volume of fresh air cannot be drawn in through the grate. This fact is demonstrated daily by opening the fuel door of the firebox when the smokestaok is discharging smoke. As soon as the fuel door is opened smoke ceases to come from thesmoke-stack, because the opening of the fuel door is necessarily large in order to admit the fuel and the shovel by which it is thrown in; but the volume" of air which passes in when the fuel door is openis so great as to cool the boiler-ton prohibitive degree.

The necessary supply of oxy'genis provided, according to the present invention, by means of one'ormore inlet tubes. I extending through the water space Cflwhich surrounds thefi're-boxl The preferredlocation for the inlet or inlets is at-the front side ofthe fire-box, slightlyv below the arch G, because the flow from the fire-box, is toward the rear in forderto pass around the rear end of the arch. The inlets are disposed in 'a horizontal plane slightly above the top of the fuel so that they will never become obstructed by'the fuel. This location is otherwise desirable, because a natural draft will be caused by the forward motion The inlets I are but one element .of the combination of elements upon which this invention depends. The other element is means for drawing the fresh-air supply through the firebox, and over the fuel, whereby the oxygen is drawn into the gases and whereby the gases are drawn toward thefuel' door instead of being free to pass by the shortest course over the arch. For this purpose a mechanical fa'n is perhaps the best means, and the drawings include such fan, which is disposed in the throat which extends through the water space C to admit fuel. The fan is indicated at J. It is affixed to a driven shaft j which extends through the fuel door H. A plate K extends over the top of the fan and is affixed to the door. The fan is driven in a direction which will cause it to draw, the gases against the door; but sufficient space is left between .the fan and door to enable the gases to flow in the opposite direction over the fire before passing over the. arch. The plate K is provided to form a-partition between the current flowing in one directionand the counter-current, and the door'is provided with curved plates k which are adapted to deflectthe gases and facilitate the reversal of directio v The shaft 7' may be driven by any suitable means. The drawings include an electric motor L which is attached to the outer side of the door H and which affords the necessary bearings for the shaft. The motor and the shaft bearings being entirely outside the fire-box and inthe out-of-door atmosphere, may be kept sufficiently cool to prevent them from being damaged by the heatedga'ses. which pass around the fan. When the door is opened the .fan is, of course, removed from the throat through which the fuel is supplied.

The effect of the fan is to draw the gases, and the air which enters through the openings I, against the rear of the fire-box and over the hottest part of the fire. The gases are thereby retained for a greater length of time in the fire-box and are consequently consumed more completely than if they were entirely free to pass over the arch into the tubes D. Not only are the gases more thoroughly consumed, .but the cinders which are entrained in the-draft are drawn over the hottest part of the fire and held in suspense temporarily so that they are subjected to the greatest heat for a to consume them.

The present invention is a smoke prevent-er rather thana smoke consumer, and

period of time sufficient 40 may be distinguished as follows: A smoke consumer-comprises means for conducting the smoke from the smoke-box at thefront of the boiler back into the fire-box where it is more or less consumed. One infirmity of such smoke consumers is that the smoke and cinders are permitted to pass through the fire-tubes or other conduits before they are consumed, thus causing an undesirable deposit upon the same. The means hereinbefore described for supplying fresh air through the .openings 1 and for drawing said air to the rear of the fire-box and for mixing the gases beforethe same pass over the arch, are adapted to cause substantially complete combustionof the gases and the "consumptionof the cinders before the same escape from the re-box; so that there will belittle if any soot or smoke or cinders allowed to pass out from the fire-box. By

thus improving the initial combustion in the fire-box, it becomes unnecessary to conduct '7 the gases back into the fire-box from the smoke-box at the front.

The size and number of the openings 1 may be varied as desired, and any suitable the most desirable. The essential feature of the invention is, admitting oxygen at one side of the fire-box above the fuel level and drawing the oxygen across the fire to the opposite side of the fire-box, thereby holding the gases in the fire-box for a greater period of time than if they were entirely free to follow the natural course of the draft.

Fig. 5 shows ascreen M in front of the fan, for preventing the cinders from passing through and around the fan with the gases. The object of making this provision is to keep the cinders where the heat is greatest and to avoid clogging the passage behind and around the fan. The cinders which are drawn against the screen are held there by the fan draft untilthey are consumed, but the finer cinders which would otherwise pass through the interstices of the screen are consumed before they reach the screen. The other'elements of the invention may be used without the screen with good result, but a greater degree of efliciency is obtained when the screen is used.

Fig. 6 shows screens over the ends of one of the inlet tubes I. All the tubes I may be provided with screens in the same way. The screens 0 at the outer ends prevent dirt from entering from without, and the screens P at the inner ends prevent fuel from entering, thus avoiding causes of clogging.

Having thus explained the nature of my said invention, and described a way of constructing and using the same, although without attempting to set forth all the forms in which it may be made or all the modes of its use, what I claim is:

1. In a furnace, the combination of the combustion chamber with its grate, an arch extending rearwardly from thefront of the combustion chamber over the grate and spaced therefrom and a fan in the rear part of the combustion chamber and so arranged as to draw the gases to the rear, mix them and project them back into the chamber so as to pass out over the arch.

2. ,In a furnace having an arch opposite the fuel door,.an air inlet under the arch in the wall opposite said door, a fan between said arch and door for drawing air from said inlet toward said door andfor drawing fuel gases toward said door and mixing said fuel gases "and air before the same pass over said arch.

3. In a furnace having an arch opposite the fuel door, a fan between said arch and fuel door and driving means for said fan whereby the gases are drawn from under said arch, mixed, and precipitated against said door, and deflected by sald door toward said arch.

4. In a furnace, the combination with a fire-pot having a grate, a draft flue'in one Wall, and a fuel door in another wall; of a,

fan arranged between said door and the fuel undergoing combustion, and means for the fuel, mix said gases, and precipitate the same against said door whereby they are deflected back over the fuel before entering 15 said flue.

In testimonywhereof I have aflixed my signature, in presence of two witnesses.

BENJAMIN F. B. FAIRBROTHER.

VVit-nesses:

WALTER P. ABELL, P. W. PEzzE'r'rI. 

